Expensive cars and characteristically designed vehicles are always in danger of being stolen. Many cases of such theft are actually reported and cause vehicle owners to feel uneasy.
Various security apparatuses are devised as countermeasures against the theft. One example is an immobiliser (electronic lock). When the immobiliser is active, any key other than the qualified one cannot start the engine.
For example, the immobiliser is constructed as follows. A small electronic communication chip called a transponder is embedded in an engine key (in its grip) for a vehicle. An identification code (ID code) is previously recorded in the transponder. When the engine key is inserted into a key cylinder on the vehicle, the transponder's ID code is transmitted to an antenna provided for the key cylinder and is read. The read ID code is collated with an ID code that is prestored in an ECU (Electronic Control Unit). A match between these ID codes authenticates that the used engine key is the qualified one. This permits the engine to be ignited and a fuel to be injected. The immobiliser turns off.
A possible difference between the ID codes for the engine key and the vehicle inhibits the engine from being ignited and a fuel from being injected. The immobiliser remains active. The engine key cannot be used to start the engine. There has been described the general construction of the immobiliser.
As mentioned above, a qualified key can turn off the immobiliser. The immobiliser is useless when the vehicle and the qualified key are stolen together.
To solve this problem, there is proposed a remote immobiliser system that forcibly operates the immobiliser by means of a remote operation using wireless communication. The system is constructed to be able to remotely operate the immobiliser by means of the wireless communication. A remote operation from an external system can forcibly operate the immobiliser. Turning off an ignition can immobilize the vehicle. Once the vehicle becomes immobilized, the system disallows even the qualified key from operating the vehicle and can prevent thefts from increasing.
The system cannot fully function when a vehicle is out of the wireless communication service provided by the external system. The system is ineffective when the vehicle and the qualified key are stolen together and the stolen vehicle moves outside the service range.
According to a proposed technology, the remote immobiliser system measures a time period in a predetermined expiration or counts the number of operations to start a driving source. The system automatically activates the immobiliser when the vehicle is assumed to continuously stay outside the service range over the expiration or a specified threshold value for the number of start operation counts.
Specifically, such technology is described in Patent Document 1. A vehicle may move outside the range of wireless communication to interrupt a periodic, automatic communication between the vehicle and a communication center. When this state continues over the predetermined expiration, the technology disables the vehicle's driving source from starting.
Patent Document 1: JP-A-H8-268231 (U.S. Pat. No. 5,880,679)
However, a qualified user may stay long or frequently outside the service range. The technology described in the above-mentioned patent document may continuously measure the time outside the service range over the specified expiration. Even though the vehicle is not stolen, the immobiliser operates automatically. The qualified user can turn off the immobiliser by entering a password, for example. Even the qualified user may need to frequently turn off the malfunctioning immobiliser. This imposes excessive burdens on the qualified user.